Figure 3. . Total testosterone levels (±SD) in a proficiency sample (Y-04) distributed by the College of American Pathologists, and assayed using 14 different instruments in 1556 participating laboratories in 2018.

Figure 3.

Total testosterone levels (±SD) in a proficiency sample (Y-04) distributed by the College of American Pathologists, and assayed using 14 different instruments in 1556 participating laboratories in 2018. The mean (±SD) value was 256 ± 51 ng/dL. The most frequent method (#6) was used by 353 laboratories. Method #4 is mass spectrometry, and was 7% lower than the mean of all methods. To convert total testosterone levels to nmol/L multiply by 0.0347

From: Laboratory Assessment of Testicular Function

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